In recent years secret permutations have been widely used for protecting different types of multimedia data, including speech files, digital images and videos. Based on a general model of permutation-only multimedia ciphers, this paper performs a quantitative cryptanalysis on the performance of these kind of ciphers against plaintext attacks. When the plaintext is of size M × N and with L different levels of values, the following quantitative cryptanalytic findings have been concluded under the assumption of a uniform distribution of each element in the plaintext: 1) all permutation-only multimedia ciphers are practically insecure against known/chosen-plaintext attacks in the sense that only O (log L (M N )) known/chosen plaintexts are sufficient to recover not less than (in an average sense) half elements of the plaintext; 2) the computational complexity of the known/chosen-plaintext attack is only O(n · (M N ) 2 ), where n is the number of known/chosen plaintexts used. When the plaintext has a non-uniform distribution, the number of required plaintexts and the computational complexity is also discussed. to demonstrate the real performance of the known-plaintext attack for a typical permutation-only image cipher.

The objective of this study, a parallel study to global gene expression profiling, was to identify dysregulated microRNAs (miRNAs) associated with endometrioid endometrial adenocarcinoma (EEC), examine their correlation with clinico‐pathological characteristics and identify predicted target genes of the dysregulated miRNAs. Using real‐time quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR), profiling of miRNA expression was performed in 30 EECs and 22 normal counterparts in which genome‐wide gene expression had been previously profiled and reported. Clustering analysis identified 30 miRNAs which were significantly dysregulated in EEC. The expression of a sub‐group of miRNAs was significantly correlated with clinico‐pathological characteristics including stage, myometrial invasion, recurrence and lymph node involvement. By searching for predicted miRNA targets that were linked to the dysregulated genes previously identified, 68 genes were predicted as candidate targets of these 30 dysregulated miRNAs. miR‐205 was significantly overexpressed in EECs compared with normal controls. After transfection of a miR‐205 inhibitor, the expression of miR‐205 in endometrial cancer cell line RL95‐2 cells decreased whereas its predicted target gene, JPH4, showed increased protein expression. JPH4 seems to be a real miR‐205 target in vitro and in vivo, and a candidate tumor suppressor gene in EEC. Based on this study in EEC, miRNAs predicted to be involved in tumorigenesis and tumor progression have been identified and placed in the context of the transcriptome of EEC. This work provides a framework on which further research into novel diagnosis and treatment of EEC can be focused. © 2008 Wiley‐Liss, Inc.

Recently, an image scrambling encryption algorithm of pixel bit based on chaos map was proposed. Considering the algorithm as a typical binary image scrambling/permutation algorithm exerting on plaintext of size M × (8N ), this paper proposes a novel optimal method to break it with some known/chosen-plaintexts. The spatial complexity and computational complexity of the attack are only O(32 · M N ) and O(16 · n 0 · M N ) respectively, where n 0 is the number of known/chosenplaintexts used. The method can be easily extended to break any permutation-only encryption scheme exerting on plaintext of size M × N and with L different levels of values. The corresponding spatial complexity and computational complexity are only O(M N ) and O( log L (M N ) · M N ) respectively. In addition, some specific remarks on the performance of the image scrambling encryption algorithm are presented.

An analysis of gene expression profiles obtained from cervical cancers was performed to find those genes most aberrantly expressed. Total RNA was prepared from 29 samples of cervical squamous cell carcinoma and 18 control samples, and hybridized to Affymetrix oligonucleotide microarrays with probe sets complementary to over 20,000 transcripts. Unsupervised hierarchical clustering of the expression data readily distinguished normal cervix from cancer. Supervised analysis of gene expression data identified 98 and 139 genes that exhibited >2-fold upregulation and >2-fold downregulation, respectively, in cervical cancer compared to normal cervix. Several of the genes that were differentially regulated included SPP1 (Osteopontin), CDKN2A (p16), RPL39L, Clorf1, MAL, p11, ARS and NICE-1. These were validated by quantitative RT-PCR on an independent set of cancer and control specimens. Gene Ontology analysis showed that the list of differentially expressed genes included ones that were involved in multiple biological processes, including cell proliferation, cell cycle and protein catabolism. Immunohistochemical staining of cancer specimens further confirmed differential expression of SPP1 in cervical cancer cells vs. nontumor cells. In addition, 2 genes, CTGF and RGS1 were found to be upregulated in late stage cancer compared to early stage cancer, suggesting that they might be involved in cancer progression. The pathway analysis of expression data showed that the SPP1, VEGF, CDC2 and CKS2 genes were coordinately differentially regulated between cancer and normal. The present study is promising and provides potential new insights into the extent of expression differences underlying the development and progression of cervical squamous cell cancer. This study has also revealed several genes that may be highly attractive candidate molecular markers/targets for cervical cancer diagnosis, prognosis and therapy. ' 2005 Wiley-Liss, Inc.

Consensus primers targeting human papillomaviruses (HPVs) have biases in sensitivity toward certain HPV types. We applied 3 primer sets (GP51/61, MY09/11, PGMY09/11) in parallel on 120 Chinese cervical cancer specimens. GP51/61 exhibited a poor sensitivity for HPV52, for which the prevalence among squamous cell cervical cancer was underestimated from 14.6% to 0%. The fact that HPV52 should rank second in prevalence among squamous cell cervical carcinoma in Hong Kong could be missed if GP51/61, a worldwide commonly used primer set, was selected for HPV detection. Biases in HPV type-specific sensitivity may result in misprioritization of vaccine candidates. ' 2005 Wiley-Liss, Inc.Key words: human papillomavirus; detection; genotype; vaccine; Chinese; Hong Kong; PCR Cervical cancer is the second most common cancer in women worldwide. Strong and consistent evidence accumulated over the past 2 decades confirms the aetiologic role of human papillomaviruses (HPVs) and provides a strong impetus for developing HPV vaccines to prevent cervical cancer. More than 100 HPV types have been identified, and at least 30 have been found in cervical cancers. 1 Given the diversity of HPV types and the largely typespecific immunity after natural infections, 2-4 it is important to delineate the prevalence of different HPV types found in cervical cancers so as to guide the selection of vaccine candidates. Most studies on HPV have employed consensus primers with an intention to cover a broad spectrum of HPV types. With the more than 10% sequence variation between HPV types, biases in sensitivity of a given primer set toward certain types could happen. In our study, we examined the influence of detection methods on assessing the prevalence of HPVs and thus their priority as cervical cancer vaccine candidates. Material and methodsA total of 120 cervical cancer specimens (105 fresh frozen and 15 paraffin embedded; 89 squamous cell carcinoma, 26 adenocarcinoma, 4 adenosquamous carcinoma and 1 lymphoepitheliod carcinoma) collected from Hong Kong Chinese aged 26-84 years (mean 55 years; SD 13.9) were examined. Total DNA was extracted by the QIAamp DNA mini kit (QIAGEN, Hilden, Germany) and with the quality of extracted preparations confirmed by beta-globin PCR. 5 The clinical materials were collected with a written informed consent. Our study was approved by the local institutional ethics committee, and the human experimentation guidelines of the local institute were followed in the conduct of our study.HPV detection and typing was accomplished by 3 different methods in parallel. In the first method, HPV DNA was amplified by the GP51/61 primers that target an approx. 150 bp fragment of the L1 region. 5,6 The HPV type was identified by direct sequencing of PCR amplicons. In the second method, the MY09/ 11 primers that target an approx. 450 bp fragment of the L1 region was used for PCR. 7,8 HPV type was identified by restriction fragment length polymorphisms (RFLPs) using endonucleases RsaI and DdeI as previously described. 8 Ambiguous RFLPs w...

In this paper, some existing perceptual encryption algorithms of MPEG videos are reviewed and some problems, especially security defects of two recently proposed MPEG-video perceptual encryption schemes, are pointed out. Then, a simpler and more effective design is suggested, which selectively encrypts fixed-length codewords (FLC) in MPEG-video bitstreams under the control of three perceptibility factors. The proposed design is actually an encryption configuration that can work with any stream cipher or block cipher. Compared with the previously-proposed schemes, the new design provides more useful features, such as strict size-preservation, on-the-fly encryption and multiple perceptibility, which make it possible to support more applications with different requirements. In addition, four different measures are suggested to provide better security against known/chosen-plaintext attacks.Comment: 10 pages, 5 figures, IEEEtran.cl

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MicroRNAs (miRNAs) play an important role in a variety of physiological as well as pathophysiological processes, including carcinogenesis. The aim of this study is to identify a distinct miRNA expression signature for cervical intraepithelial neoplasia (CIN) and to unveil individual miRNAs that may be involved in the development of cervical carcinoma. Expression profiling using quantitative real-time RT-PCR of 202 miRNAs was performed on micro-dissected high-grade CIN (CIN 2/3) tissues and compared to normal cervical epithelium. Unsupervised hierarchical clustering of the miRNA expression pattern displayed a distinct separation between the CIN and normal cervical epithelium samples. Supervised analysis identified 12 highly differentially regulated miRNAs, including miR-518a, miR-34b, miR-34c, miR-20b, miR-338, miR-9, miR-512-5p, miR-424, miR-345, miR-10a, miR-193b and miR-203, which distinguished the high-grade CIN specimens from normal cervical epithelium. This miRNA signature was further validated by an independent set of high-grade CIN cases. The same characteristic signature can also be used to distinguish cervical squamous cell carcinoma from normal controls. Target prediction analysis revealed that these dysregulated miRNAs mainly control apoptosis signaling pathways and cell cycle regulation. These findings contribute to understanding the role of microRNAs in the pathogenesis and progression of cervical neoplasm at the molecular level.